The present invention relates to an intervertebral implant having a top surface configured to engage a first vertebral body, a bottom surface configured to engage a second vertebral body and a side wall connecting the top surface and the bottom surface, and a hollow space formed within the implant and accessible through an elongate opening extending through a portion of the side wall.
The invention further relates to a device for inserting the intervertebral implant into a body, comprising a drive shaft including an engagement portion for engaging a hollow space of an intervertebral implant in a form-fit connection, and a sleeve movably guiding the drive shaft and having a longitudinal axis.
An intervertebral implant which is configured to be engaged by an insertion device for insertion of the implant between first and second vertebral members is known from DE 10 2008 045 174 A1. The intervertebral implant has an insertion opening including a slit-like elongated shape that extends through the side wall. The insertion opening provides access to an inner space of the implant for the insertion device. The insertion device has a sleeve and a shaft guided through the sleeve, wherein an elongate support projection having a cylindrical support surface is provided at a distal end of the shaft.
The shaft can be rotated with respect to the sleeve, such that the elongate support projection is first inserted through the slit-like opening into the inner space and then rotated to establish a connection. The shaft may then be drawn back with respect to the sleeve in order to connect the cylindrical support surface of the shaft with a corresponding cylindrical recess formed at an inner wall of the inner space in a direction transverse to the insertion opening in a form-fit manner. This connection allows for rotating and selectively positioning the implant with respect to the insertion tool, wherein its shaft follows the path of the slit-like opening. A counterforce and sliding engagement is achieved by an appropriately shaped front wall of the distal end and of the sleeve, which engages the side wall of the implant around the insertion opening.
Another insertion device, which has a shaft-like section that may be rotated after insertion to establish a connection between the device and an intervertebral implant, is disclosed in US 2007/0162129 A1. At the distal end of the shaft, an elongated head having a cuboid shape is provided. Drawing back the distal end then sandwiches an outer wall of the implant between a back side surface of the cuboid-Ss shaped elongate head and a stop provided at distal end of a sleeve-like first section of the device.
U.S. Pat. No. 8,673,012 B2 also discloses an intervertebral spacer which in FIGS. 8A-C thereof has an inner cavity and a through hole, through which a portion of an insertion tool having transverse extensions may be inserted and then rotated, to establish a connection between a trailing end of the intervertebral spacer and the insertion tool. Thereby, an appropriately shaped front wall of the insertion tool having engagement features is pressed onto a side wall of the intervertebral spacer.
Documents EP 2 535 021 A1 and EP 2 535 022 A1 provide other examples of devices suitable for insertion of an intervertebral implant into a body following transforaminal lumbar interbody fusion surgery techniques (TLIF). The TLIF technique involves approaching the spine from the side of the spinal canal through a midline incision in the patients back. This approach greatly reduces the amount of surgical muscle dissection and minimizes the nerve manipulation required to access the vertebrae, discs and nerves.